1. Field
This application relates generally to wireless communication and more specifically, but not exclusively, to interference mitigation.
2. Introduction
Deployment of a wireless communication system typically involves implementing some form of interference mitigation scheme. In some wireless communication systems, interference may be caused by neighboring wireless nodes. As an example, in a cellular system wireless transmissions of a cell phone or a base station of a first cell may interfere with communication between a cell phone and a base station of a neighboring cell. Similarly, in a Wi-Fi network, wireless transmissions of an access terminal or an access point of a first service set may interfere with communication between an access terminal and a base station of a neighboring service set.
U.S. Patent Application Publication No. 2007/0105574 describes a system where fair-sharing of a wireless channel may be facilitated by joint scheduling of a transmission by transmitting and receiving nodes through the use of a resource utilization message (“RUM”). Here, a transmitting node may request a set of resources based on knowledge of resource availability in its neighborhood and a receiving node may grant the request based on knowledge of resource availability in its neighborhood. For example, the transmitting node may determine channel availability by listening to receiving nodes in its vicinity and the receiving node may determine potential interference by listening to transmitting nodes in its vicinity.
In the event the receiving node is subjected to interference from neighboring transmitting nodes, the receiving node may transmit a RUM in an attempt to cause the neighboring transmitting nodes to limit their interfering transmissions. According to related aspects, a RUM may be prioritized (e.g., weighted) to indicate not only that a receiving node is disadvantaged (e.g., due to the interference it sees while receiving) and desires a collision avoidance mode of transmission, but also the degree to which the receiving node is disadvantaged.
A transmitting node that receives a RUM may utilize the fact that it has received a RUM, as well as the priority thereof, to determine an appropriate response. For example, the transmitting node may elect to abstain from transmitting, may reduce its transmit power during one or more designated timeslots, may transmit on another carrier, may ignore the RUM, or may take some other action. The advertisement of the RUMs and associated priorities may thus provide a collision avoidance scheme that is fair to all nodes in the system.